1. Field of the Invention
The present invention relates to an inverter generator in which AC electric power generated by a motor is once converted into DC power and further converted into AC power with a desired frequency.
2. Description of the Related Art
A synchronous electric motor driven by a motor such as a combustion engine is used as an electric generator for generating alternating current electric power. An electric generator sometimes further contains a converter by which a generated power is once converted into a direct current electric power and then converted into alternating current electric power for output. An electric generator with such a converter, generally referred to as “inverter generator”, serves some benefits such as controllability of voltage and frequency of output electricity independent of those of originally generated by the synchronous electric motor.
A converter in an inverter generator requires information about electrical angles in regard to the synchronous electric motor to control its conversion mode. Thus an inverter generator so far needs to have additional sensors on its synchronous electric motor to inform electrical angles to its converter. JP2005-295626 and JP2007-185099 discloses related arts.